'Doctor Who' writer: 'New episode is unusual'

Doctor Who writer Tom MacRae has dropped hints about his new episode of the show.

MacRae told The Daily Telegraph that his new installment, which will air tenth in the current run, is his "most accomplished piece of plotting ever".

"What's interesting is that the requirements of the script meant that for various reasons nothing has gone out about it at all," he explained. "We didn't do much location filming, and the way the guest characters work is unusual, so no-one knows anything about my episode."

The scribe, who previously wrote the 'Rise of the Cybermen / The Age of Steel' two-parter for the show's 2006 series, added that his new story contains "a really big surprise".

"I'm amazed we've kept it this secret," he admitted. "All I will say is that it's an unusual episode and it's really great."

MacRae also dismissed early rumors about his episode and denied that the adventure had borne the working title of 'The Green Anchor'.

"It has never been called that!" he objected. "There's speculation about it which is wrong."